Subtraction of numbers in the range 100000

### 1.1. Knowledge to remember

**85674 – 58329 = ?**

85674 – 58329 = …

- 4 does not subtract 9, take 14 minus 9 equals 5, write 5 remember 1.
- 2 plus 1 equals 3; 7 minus 3 equals 4, write 4.
- 5 does not subtract 8, take 15 minus 8 equals 7, write 7 remember 1.
- 5 plus 1 equals 6; 8 minus 6 equals 2, write 2.

### 1.2. Solving Textbook Exercises

**Lesson 1:** Calculate

\(\underline { – \begin{array}{*{20}{c}}

{92896}\\

{65748}

\end{array}} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\underline { – \begin{array}{ *{20}{c}}

{73581}\\

{36029}

\end{array}} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\underline { – \begin{array}{*{20}{c}}

{59372}\\

{53814}

\end{array}} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\underline { – \begin{array}{*{20}{c}}

{32484}\\

{\,\,\,9177}

\end{array}} \)

**Solution guide:**

- Perform subtraction of numbers from right to left.

\(\begin{array}{l}

\underline { – \begin{array}{*{20}{c}}

{92896}\\

{65748}

\end{array}} \\

\,\,\,\,\,\,27148\,

\end{array}\) \(\begin{array}{l}

\underline { – \begin{array}{*{20}{c}}

{73581}\\

{36029}

\end{array}} \\

\,\,\,\,\,\,37552

\end{array}\) \(\begin{array}{l}

\underline { – \begin{array}{*{20}{c}}

{59372}\\

{53814}

\end{array}} \\

\,\,\,\,\,\,\,5558

\end{array}\) \(\begin{array}{l}

\underline { – \begin{array}{*{20}{c}}

{32484}\\

{\,\,\,9177}

\end{array}} \\

\,\,\,\,\,23307

\end{array}\)

**Lesson 2:** Calculate then calculate

a) 63780 – 18546 b) 91462 – 53406 c) 49283 – 5765

__Solution guide:__

- Set calculation: Write the calculation so that the digits are in the same row and column together.
- Calculate: Perform subtraction from right to left in turn.

a)

\(\begin{array}{l}

\underline { – \begin{array}{*{20}{c}}

{63780}\\

{18546}

\end{array}} \\

\,\,\,\,\,45234

\end{array}\)

b)

\(\begin{array}{l}

\underline { – \begin{array}{*{20}{c}}

{91462}\\

{53406}

\end{array}} \\

\,\,\,\,\,38056

\end{array}\)

c)

\(\begin{array}{l}

\underline { – \begin{array}{*{20}{c}}

{49283}\\

{\,\,\,5765}

\end{array}} \\

\,\,\,\,\,43518

\end{array}\)

**Lesson 3:** A distance of 25 850m, of which 9850m has been paved. How many kilometers of unpaved road are left?

__Solution guide:__

- To find the solution, we subtract the length of the whole road from the length of the paved road.

*Solution*

Length of unpaved road:

25850 – 9850 = 16 000 (m)

Change: 16000m = 16 km

Answer: 16 km.

.

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